Study On Amination Of Graphene And Its Enhancement Of Soy Protein Adhesive

To improve the water-resistant bonding performance of soybean protein adhesive,improve the problems of high brittleness and a large amount of crosslinking agent caused by crosslinking modification,this study used amine compounds to modify graphene oxide GO to prepare aminated graphene(EGO and FGO),together with the epoxide crosslinking agents PAE and TGA,build a cross-linking network structure to improve the water-resistant bonding performance of soybean protein adhesives.Through the characterization and analysis of viscosity,toughness,water swelling index,functional groups,thermal stability,cross-section morphology of cured adhesive and water-resistant bonding strength of plywood,the influence of amino graphene oxide on viscosity,solid content,swelling rate,water-resistance bonding properties of cross-linked modified soybean protein adhesive and its mechanism were clarified.The main research conclusions are as follows:(1)Succinic anhydride reacts with diethylene triamine to form a hyperbranched polyamide,and obtains FGO by nucleophilic ring-opening reaction or amidation reaction with graphene oxide;EGO is obtained by grafting GO with ethylenediamine.Compared with the soybean protein(SPI)adhesive,when the amount of EGO added is 0.4wt%,the water-resistant adhesive strength of the prepared plywood is 0.81MPa;when 0.4wt% FGO modified soybean protein adhesive is added,the water-resistant plywood is prepared The glue strength(63?)is increased by 181% to 1.18 MPa,both of which meet the requirements of Class II plywood standards.(2)FGO modified soybean protein adhesive reduces the porosity of the cross-section of the cured adhesive and becomes dense and wrinkled.Compared with the unmodified protein adhesive,the addition of 0.4wt% FGO reduced the solubility fraction of the adhesive from 80.12% to 26.84%,a decrease of 198.5%;the swelling rate decreased by 281.0%,from 249.45% to 65.47%.The amount of PAE added in the modification process is only 0.75wt%,which is about 70%-90% lower than that of traditional chemical crosslinking modification.The wood breakage rate of plywood damaged surface increased from less than 10% when unmodified to more than 90%.(3)The enhancement mechanism of FGO on soybean protein isolate adhesive is:(1)FGO crosslinks with SPI through the cross-linking agent PAE,consumes the hydrophilic group of protein molecules and forms a uniform and dense network structure,preventing the intrusion of water molecules;(2)GO's two-dimensional flexible sheet structure and the hyperbranched polymer's highly branched structure work together to change the soybean protein adhesive system from brittleness to toughness,which strengthens and toughens the adhesive.